This invention relates to a method of relieving pain by using a pharmaceutical combinations of compounds having analgesic activity.
U.S. Pat. No. 3,752,826, issued to Carson on Aug. 14, 1973, discloses a class of anti-inflammatory 5-aroyl-pyrrole alkanoic acids. The compound 1,4-dimethyl-5-p-chlorobenzoyl-pyrrole-2-acetic acid, commonly known as zomepirac and having the formula ##STR1## is specifically disclosed. J. Castaner and K. Hillier, "Drugs of the Future", vol. 2, pp. 698-701, 1977, disclose that zomepirac is an analgesic agent for the control of moderate to severe pain.
Acetaminophen, N-(4-hydroxyphenyl)acetamide, was first used in medicine by Van Mering in 1893, but only since 1949 has it gained in popularity as an effective alternative to aspirin for analgesic uses. Acetaminophen has been widely administered with a variety of other drugs, including opioid analgesics such as codeine, and antipyretic analgesics, such as aspirin. Goodman et al., "The Pharmacological Basis of Therapeutics", Fifth Ed., Macmillan Publishing Co., 1975, pp. 348-349, state that it is likely that an effective dose of an opioid or of an antipyretic analgesic such as aspirin will add to the analgesic effect of acetaminophen. A. W. Pircio et al., Arch. int. Pharmacodyn., 235, 116-123 (1978), however, have reported unexpectedly enhanced analgesic action with a 1:125 mixture of butorphanol, ##STR2## and acetaminophen; whereas a similar 1:10 combination did not show statistically-significant analgesic enhancement.
G. Stacher et al., Int. J. Clin. Pharmacol. Biopharmacy, 17, 250-255 (1979) report that coadministration of tolmetin, ##STR3## and acetaminophen permits a marked reduction of the dose of tolmetin needed to produce an analgesic effect in experimentally induced pain in human subjects. U.S. Pat. No. 4,132,788, issued to S. Wong on Jan. 2, 1979, discloses potentiation of the antiarthritic activity of 5-aroyl-1-(lower)alkylpyrrole-2-acetic acid derivatives by combination with aspirin or acetominophen. Antiarthritic potentiation with mixtures of tolmetin with acetaminophen and aspirin and zomepirac with acetaminophen and aspirin is specifically disclosed. The experimental procedures employed by Wong were not designed to detect pain, and furthermore, pain does not necessarily accompany inflammation or the development of arthritic disease in animals or in man.
Methods of relieving pain with analgesic combinations allowing reduced dosages are constantly being sought because thereby relief of pain can be obtained with a diminution of the expected side effects and toxicity which would result from the otherwise required higher dosages.